Abstract Aims In peripartum cardiomyopathy (PPCM), electrocardiography (ECG) and its relationship to echocardiography have not yet been investigated in large multi-centre and multi-ethnic studies. We aimed to identify ECG abnormalities associated with PPCM, including regional and ethnic differences, and their correlation with echocardiographic features. Methods and results We studied 411 patients from the EURObservational PPCM registry. Baseline demographic, clinical, and echocardiographic data were collected. ECGs were analysed for rate, rhythm, QRS width and morphology, and QTc interval. The median age was 31 [interquartile range (IQR) 26–35] years. The ECG was abnormal in > 95% of PPCM patients. Sinus tachycardia (heart rate > 100 b.p.m.) was common (51%), but atrial fibrillation was rare (2.27%). Median QRS width was 82 ms [IQR 80–97]. Left bundle branch block (LBBB) was reported in 9.30%. Left ventricular (LV) hypertrophy (LVH), as per ECG criteria, was more prevalent amongst Africans (59.62%) and Asians (23.17%) than Caucasians (7.63%, P < 0.001) but did not correlate with LVH on echocardiography. Median LV end-diastolic diameter (LVEDD) was 60 mm [IQR 55–65] and LV ejection fraction (LVEF) 32.5% [IQR 25–39], with no significant regional or ethnic differences. Sinus tachycardia was associated with an LVEF < 35% (OR 1.85 [95% CI 1.20–2.85], P = 0.006). ECG features that predicted an LVEDD > 55 mm included a QRS complex > 120 ms (OR 11.32 [95% CI 1.52–84.84], P = 0.018), LBBB (OR 4.35 [95% CI 1.30–14.53], P = 0.017), and LVH (OR 2.03 [95% CI 1.13–3.64], P = 0.017). Conclusions PPCM patients often have ECG abnormalities. Sinus tachycardia predicted poor systolic function, whereas wide QRS, LBBB, and LVH were associated with LV dilatation.